From c86bb6e9f0353dde3ec01eebe0162aa754aeea37 Mon Sep 17 00:00:00 2001
From: Ryan Malloy <ryan@supported.systems>
Date: Thu, 5 Mar 2026 15:42:56 -0700
Subject: [PATCH] Add embedding docs and LTspice engine to llms.txt

---
 frontend/public/llms.txt | 52 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 49 insertions(+), 3 deletions(-)

diff --git a/frontend/public/llms.txt b/frontend/public/llms.txt
index 18cd6f6..9fef57d 100644
--- a/frontend/public/llms.txt
+++ b/frontend/public/llms.txt
@@ -1,6 +1,6 @@
 # SpiceBook
 
-> Notebook interface for SPICE circuit simulation. Create, edit, and run SPICE netlists in a cell-based notebook UI with waveform visualization and schematic generation. Powered by ngspice.
+> Notebook interface for SPICE circuit simulation. Create, edit, and run SPICE netlists in a cell-based notebook UI with waveform visualization and schematic generation. Supports ngspice and LTspice engines.
 
 Base URL: `https://spicebook.warehack.ing`
 
@@ -46,7 +46,7 @@ POST /api/notebooks
 }
 ```
 
-Both fields are optional. Defaults: title = `"Untitled Notebook"`, engine = `"ngspice"`.
+Both fields are optional. Defaults: title = `"Untitled Notebook"`, engine = `"ngspice"`. Supported engines: `"ngspice"`, `"ltspice"`.
 
 **Response** `201`
 ```json
@@ -419,7 +419,7 @@ For AC analysis (`is_complex: true`), `y_magnitude_db` and `y_phase_deg` contain
 
 ## SPICE Netlist Primer
 
-SpiceBook uses **ngspice** as its simulation engine. Netlists are plain text describing a circuit and the analysis to perform.
+SpiceBook supports **ngspice** and **LTspice** as simulation engines. Netlists are plain text describing a circuit and the analysis to perform.
 
 ### Basic structure
 
@@ -555,3 +555,49 @@ GET /health
 ```json
 {"status": "ok", "version": "2026.02.13"}
 ```
+
+---
+
+## Embedding
+
+Any notebook can be embedded on a third-party page via iframe. No API key or authentication is required.
+
+### Embed URL
+
+```
+https://spicebook.warehack.ing/embed/{notebook_id}?theme=dark
+```
+
+| Parameter | Values | Default | Description |
+|-----------|--------|---------|-------------|
+| theme | `dark`, `light` | `dark` | Initial color theme |
+
+### iframe snippet
+
+```html
+<iframe
+  src="https://spicebook.warehack.ing/embed/{notebook_id}?theme=dark"
+  width="100%" height="600"
+  style="border: 1px solid #334155; border-radius: 8px;"
+  allow="clipboard-write"
+></iframe>
+```
+
+The embed renders the notebook read-only with working simulation — viewers can run SPICE cells and see waveform results.
+
+### Theme control via postMessage
+
+The parent page can switch the embed's theme at runtime:
+
+```javascript
+iframe.contentWindow.postMessage(
+  { type: 'spicebook-theme', theme: 'light' },
+  '*'
+);
+```
+
+Accepted values for `theme`: `"dark"`, `"light"`. Other messages are ignored.
+
+### Discovering the embed snippet
+
+In the notebook editor UI, the **Embed** button in the toolbar opens a popover with a ready-to-copy iframe snippet and a theme toggle.